Its not rocket science.

BTC dominance is rising as many investors pull out of alts.

Steem isnt dropping very hard in terms of btc value, just slowly.

If it was dropping as hard as say eos, steem woul be at 0.4-0.3 in terms of sat value.

Simply put, btc going down, makes alts go down, btc going up without external money, makes alts go down(since the money is flowing from alt to btc)